SOLUTION: My current age is 4 times what my sister's age was 20 years ago. i am now twice as old as i was 20 years ago. ten years ago, my sister's age was 1/2 of my current age. ten years ag

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Question 1119821: My current age is 4 times what my sister's age was 20 years ago. i am now twice as old as i was 20 years ago. ten years ago, my sister's age was 1/2 of my current age. ten years ago, my age was 1.5 times my sister's age. what is my current age?
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
x, sister's age
y, your age

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My current age is 4 times what my sister's age was 20 years ago.
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y=4%28x-20%29


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i am now twice as old as i was 20 years ago. ten years ago, my sister's age was 1/2 of my current age.
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system%28y=2%28y-20%29%2Cx-10=%281%2F2%29y%29

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ten years ago, my age was 1.5 times my sister's age. what is my current age?
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y-10=%283%2F2%29%28x-10%29



Use what you need. Decide if your results make sense.


highlight%28y=40%29---------your age now
-
highlight%28x=30%29---------sister's age now

Answer by ikleyn(52802) About Me  (Show Source):
You can put this solution on YOUR website!
.
1.  This statement "i am now twice as old as i was 20 years ago" implies that your current age is 40 years.

    So, it is just your answer to the problem's question.


    The rest is simply to check that there is no contradictions with the remaining statements.



2.  If so, then the statement "My current age is 4 times what my sister's age was 20 years ago"  implies 
    that your sister age 20 years ago was 10 years; hence, her age is 30 years now.



3.  "ten years ago, my sister's age was 1/2 of my current age" - Correct.



4.  "ten years ago, my age was 1.5 times my sister's age."  - Correct.


So,  again:   the only statement  "i am now twice as old as i was 20 years ago"  is just enough to answer the problem question.

The rest of the statements add  NOTHING  to get the answer.

They only need your care to check if there is no contradiction with the answer.